Continuous spin-casting is a process where molten metal is forced through a nozzle onto a substrate where it freezes and is spun off as ribbon product. The contacting interface between the substrate and the molten metal affects the surfaces (top or bottom sides) of the resulting ribbon product. With respect to thicker ribbon product, i.e. ribbon product having a thickness greater than about 50 mm, the effects on the surface only impact a small fraction of the thickness of the ribbon product and thus generally are negligible. However, as the ribbon product becomes thinner, i.e. has a ribbon product thickness less than about 1 mm, the effects on the surface of the ribbon product impact a larger percentage of the thickness of the ribbon product. As a result, substantially single step continuous casting has only been used to a limited extent commercially to produce flat product. One example of such a continuous spin-casting process that has been used commercially is disclosed in U.S. Pat. No. 4,142,571 to Narasimhan which is herein incorporated by reference.
Instead one prior technique to produce a thin ribbon product, such as aluminum sheet, is to first cast, on the order of about 500 mm thick, a thick slab using the twin-roll process or otherwise and then to subject the slab to a sequence of hot and cold rolling stages until the thickness of the slab is reduced on the order of 104:1. Although this process works, it requires a number of steps, a large capital investment, generates considerable scrap and consumes a relatively large amount of energy.
Mechanical conditioning of the substrate to manipulate cast quality and to obtain thicker ribbon product has been suggested in, “The early stages in aluminum solidification in the presence of a moving meniscus” by D. Weirauch in, “The integration of Material, Process and Product Design”, pages 183–191 and by U.S. Pat. No. 4,705,095 to Gasper which are both herein incorporated by reference.